Compressor



May 6, 1947. w. J. ROULEAU 2,420,098

l COMPRESSOR Filed Dec.` 7. V1944 Patented May 6, 1947 UNITED STATESPATENT OFFICE COMPRESSOR Wilfred J. Rouleau, Quincy, Mass.

Application December 7, 1944, Serial No. 566,984

6 Claims.

This invention relates to compressors for compressing air and other gasand particularly to the means for cooling the air as it is compressedthereby to absorb the heat of compression.

One common method employed for thus cooling the air is to spray waterinto the cylinder during the operation of the compressor, and a pump isusually used for this purpose.

It is an object of my present invention to provide a simplified butnovel construction by which the water or other cooling medium will beautomatically sprayed into the cylinder without the use of any pump solong as the pressure in the vcylinder is less than the maximum pressuredeveloped by the compressor, said spraying operation ceasing as soon asthe maximum pressure within the cylinder has been reached.

In order to give an understanding of the invention, I have illustratedin the drawings a selected embodiment thereof which will now bedescribed after which the novel features will be pointed out in theappended claims.

In the drawings:

Fig. 1 is a view partly in section of a compressor embodying myinvention.

Fig. 2 is a fragmentary view, also partly in section, showing theshutoff and vent valve for the tank containing the cooling medium.

In the drawings I indicates generally a compressor of any suitable orknown construction, said compressor being provided with the usualcylinder 2 in which operates the piston 3. The compressor herein shownis of the double acting type, although the invention is equallyapplicable to a compressor of the single acting type. The compressor isshown as having the usual intake chamber 4 which is supplied with gasesto be compressed through the intake pipe 5, said chamber d communicatingwith the cylinder through the medium of the usual inlet valves 6. Thecompressor is also provided with the usual discharge chamber 'I whichcommunicates with the ends of the cylinder through discharge valves 8,and said chamber 'I is connected by a discharge pipe B to a storage tankIII in which the air or other gas to be compressed is stored. Said tankIII has a discharge pipe II through which the compressed gases may bewithdrawn and it also is provided with the usual drain pipe I2. Theparte thus far described are such as are commonly found in compressorsof this type.

Each cylinder head of the cylinder 2 is provided with a spray nozzle I3through which water or other cooling medium may be sprayed into thecylinder. These nozzles I3 are ,suppliedl with the cooling mediumthrough a supply pipe I4 which is provided with two branches I5 and I6,one leading to one ofthe nozzles I3 and the other leading to the othernozzle I3. The supply pipe I4 is illustrated as having a check valve I1therein and also a shutoff valve I8.

In accordance with my present invention I provide a tank -IS whichcontains the water or other cooling medium 2B and to which the supplypipe I4 is connected. The tank I9 is connected to the storage tank Illso that the cooling medium 20 in the tank I9 is subjected to the samepressure as that in the storage tank.

For this purpose the upper end of the tank I9 is connected by a pipe 2lto the storage tank and as will be obvious by this means the coolingmedium in the tank 20 is continuously subjected to the pressure in thestorage tank Il). With this construction and so long as the shutoiivalve IB in the pipe I4 is open, the pressure to which the coolingmedium 20 in the tank I9 is subjected will force cooling medium througheach nozzle I3 so long as the pressure in the corresponding end of thecylinder chamber is less than the pressure in the storage tank I0. When,however, during the compression stroke the pressure in the cylinder 2has reached its maximum and the corresponding-discharge valve 8 opens topermit discharge of the compressed gas, the delivery of a spray of waterfrom the nozzle I3 will cease because of the fact that the pressure atthe discharge end of the nozzle has been equalized with that on thecooling medium in the tank I9.

The piston 3 in Fig. 1 is shown as at the left hand end of its stroke,and during its movement toward the left, which is its suction stroke forthe right hand end of the cylinder, the pressure in the cylinder will beless than that in the storage tank, and therefore less than that towhich the cooling medium Z' in the tank I9 is subjected, and therefore,the cooling medium will be automatically sprayed into the cylinder asshown in Fig. 1. During the movement of the piston 3 to the right, theair or gas in the cylinder will be compressed until nally the pressurein the cylinder is equal to that in the storage tank at which time thedischarge valve 8 will open and the compressed gas will be forced fromthe cylinder into the storage tank. As soon as the pressure in thecylinder has been built up so as to equalize that in the Storage tank,further delivery of cooling medium through the nozzle I3 will cease andthe cooling medium will `only' again be delivered from the 3 nozzle I3when the piston begins its suction stroke.

With this construction the use of any pump or other similar machineryfor forcing the cooling medium through the spray nozzles is entirelyeliminated, and thereby the construction and operation of the coolingmeans for the compressor is much simplied.

I propose to incorporate in the pipe 2I la threeway valve 22 by whichthe communication Vbetween the storage tank II] and the tank I9 may beclosed and the tank I9 may be vented through a vent pipe 23. 24indicates a supply pipe through which added cooling water or othercooling medium may be supplied to the tank I9 when necessary. This pipe24 has a check valve 25 therein to prevent any back flow through vthepipe 24.

The tank I9 is also shown as beingequipped with a gauge 25 by which thelevel of the cooling Vmedium V2) therein may be observed.

When the cooling medium in the tank I9 is nearexhaustion, then the valve22 is turned into the position shown in Fig. 2, ,thereby cutting off`commur,iication between the ,storage tank I and the tank I9 and openingsaid tank to the atmosphere 4through ,the vent ,pipe 23. Water or othercooling medium ,will then be supplied lto the tank 4through the supplypipe 24 Aand when the tank ,is nlled, the valve v`2.2 Yis again movedinto position to cut off the vent .but to open communication between itandthe storage tank Ill.

The spraying of water into the cylinder of the .compressor has atendency7 to wash out of the cylinder the lubricant necessary toproperly lubricate the piston. Inorder to prevent such loss 4o flubricant, I propose to supply a suitable 1ubricating liquid to the pipeI4 so that said 1ubricating liquid will mingle with the cooling mediumand thus 'be delivered to the cylinder with the spray. For this purpose,there is shown a ylubricant Vsupplying pipe 21 which is connected intothe pipe connection I4. Any suitable liquid lubricant may be supplied tothe pipe 2'I. One lubricant which is suitable for this purpose iscolloidal graphite which is known by the trade name Aguadag By thislmeans a sufcient amount of lubricant for properly lubricating thepiston Ais being constantly fed to the cylinder, thereby .avoiding anypossibility of insulcient lubrication due to the presence of the spray.

While the shutoi valve I8 may be operated in any suitable way wheneverit is desired to close or open the communication between the tank I9 andthe nozzles I 3, yet I have herein illustrated means for operating saidvalve in conjunction Vwith the control switch by which the motor for thecompressor is started and stopped, so that when the motor circuit isopened and the compressor ceases to operate, the valve I8 Will beautomatically closed, thus shutting off the supply of cooling medium tothe nozzles, while when the switch is operated to close the motorcircuit andrstart up the compressor, the valve I8 will be open so as topermit delivery of cooling medium Ato the nozzles.

I have shown I nore or less diagrammatically at 2,3. a knife switch ofany usual construction for opening and closing the circuit of the motorby which the compressor is operated, such switch including the twocontacts 29 and the knife contact 30 which is pivoted at 3| and whichcan be turned about its pivot to open and close the switch. The swingingcontact 30 has rigid therewith an arm 32 which is connected by a link 33-by closing the shutoff valve I8. With this construction, the deliveryof cooling medium to the nozzles is automatically terminated when thecompressor is shut down, and delivery is automatically re-establishedwhen the switch is closed to start up the compressor.

If desired, the three-way valve 22 may be operated automatically bymeans of a float that in turn is controlled by the level of the cooling4medium inthe tank I9. Inasmuch as floats for opening and closing avalve are used in a number of diierent arts, -I have not thought itnecessary to illustrate the oat herein.

I claim:

-1. A compressor for compressing air and other gases comprising acylinder, a piston operating therein, a spray nozzle to deliver coolingmedium to the cylinder, a tank containing the cooling medium, meansconnecting the tank to the nozzle, and means for maintaining in the tanka pressure substantially equal to the maximum pressure developed by thecompressor, whereby cooling medium will be automatically delivered fromthe nozzle into the cylinder of the compres- -sor except when thepressure in said cylinder equals or exceeds that in the tank.

2. A'compressor for compressing air and other gases comprising acylinder, a piston operating therein, a spray nozzle to deliver coolingmedium `to the cylinder, 'a storage tank to receive the gases compressedby the compressor, a second tank containing the cooling'medium, meansconnecting said second tank to the nozzle, and means connecting saidsecond tank to the storage tank whereby the cooling medium in the secondtank will be consequently subjected to the pressure in the storage tankand will thus be constantly forced through the nozzle into the cylinderexcept when the maximum pressure has been developed in said cylinder,

3. A compressor for compressing air and other gases comprising acylinder, a piston operating therein, a spray nozzle to deliver coolingmedium to the cylinder, a tank containing the cooling medium, meansconnecting the tank to the nozzle, means for maintaining in the tank apressure substantially equal to the maximum pressure developed by thecompressor, whereby cooling medium will be automatically delivered fromthe nozzle into the cylinder of the compressor except when the pressurein said cylinder equals or exceeds that in the tank, and means fordelivering a lubricant to the cooling medium prior to its delivery fromthe nozzle.

4. A compressor for compressing air and other gases comprising acylinder, a piston operating cept when the pressure in said cylinderequals or exceeds that in the tank, and means for automatically closingthe communication between the tank and the nozzle when the compressorceases operation.

5. A compressor for compressing air and other gases comprising acylinder, a piston operating therein, a spray nozzle to deliver coolingmedium to the cylinder, a tank containing the cooling medium, meansconnecting the tank to the nozzle, means for continuously subjecting thecooling medium in the tank to the maximum pressure developed by thecompressor, whereby cooling medium will be automatically delivered fromthe nozzle into the cylinder of the compressor except when the pressurein said cylinder equals or exceeds that in the tank, and means forautomatically closing the communication between the tank and the nozzlewhen the compressor ceases operation and for automatically opening saidcommunication when the compressor is started in operation,

6. A compressor for compressing air and other gases comprising acylinder, a piston operating therein, a spray nozzle to deliver coolingmedium to the cylinder, a tank containing the cooling REFERENCES CITEDThe following references are of record in the file of this` patent:

UNITED STATES PATENTS Number Name Date 224,081 Eckart Feb. 3, 1880233,432 Pitchford Oct. 19, 1880 268,348 Wood et al. Nov. 28, 1882294,299 Ostergren Feb. 25, 1902 2,042,991 Harris June 2, 1936

